I have target xml to generate from schema.  All of the XML instances
have the same global element i.e. <base>.  I would like to combine all
of the schemas into a single schema where I could generate any of the
specific instances.

sample schema one:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
  <xs:element name="base">
    <xs:complexType>
      <xs:attribute name="myNodeABC" type="xs:string"/>
      <xs:attribute name="myNodeDEF" type="xs:string"/>
    </xs:complexType>
  </xs:element>
</xs:schema>

sample schema two:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
  <xs:element name="base">
    <xs:complexType>
      <xs:attribute name="myNodeABC" type="xs:string"/>
      <xs:attribute name="myNodeXYZ" type="xs:string"/>
    </xs:complexType>
  </xs:element>
</xs:schema>

Can anyone suggest how to join these two into a single schema where
the instance document does not have namespace prefixed
elements/attributes?

I tried attributeGroups, groups, import and include elements, without
any luck.

Any help is appreciated.

Thanks,
Gordon